Ta có: \(\sqrt{a^2}+2\sqrt{\left(a-2\right)^2}\)
\(=\left|a\right|+2\left|a-2\right|\)
\(=\left|a\right|+2\left(2-a\right)\)
\(=\left[{}\begin{matrix}a+4-2a\left(0\le a< 2\right)\\-a+4-2a\left(a< 0\right)\end{matrix}\right.\)
\(=\left[{}\begin{matrix}4-a\\4-3a\end{matrix}\right.\)